The background of the invention will be discussed in two parts:
1. Field of the Invention
This invention relates to laser apparatus and processes and more particularly to a laser apparatus and process for producing laser cuts in paper.
2. Description of the Prior Art
The use of laser apparatus to produce intricate paper cuts has recently experienced great commercial success. The process and apparatus presently in use, however, utilizes a template which makes contact with a stack of paper, with the apparatus designed to exert considerable pressure on the paper to prevent smoke from condensing between the various sheets of paper. With this pressure requirement, the particular process and apparatus does not readily lend itself to use in a line with a standard printing press which is set up to handle one sheet of paper at a time with a continuous flow of paper.
Another method utilized for producing laser cut paper involves a modulation approach, in which the paper is scanned with an electronically modulated laser beam with the beam being turned on and off to provide a point by point resolution of the desired image. This approach, however, has been heretofore utilized with stationary, or very slow-moving paper, since present modulation mechanisms for use with carbon dioxide lasers do not permit a high enough modulation frequency to be achieved for the mass production required in the printing industry. Furthermore, apparatus involving direct modulation of the laser beam is complicated and expensive.
Non-contact laser-engraving apparatus has heretofore been successfully been utilized for engraving objects made of wood. One such apparatus is shown and described in U.S. Pat. No. 4,156,124, entitled "Image Transfer Laser Engraving". In the device of this patent, first and second generally parallel support tables are mounted for simultaneous synchronous rotation, with a mask or template on the first table and the work piece on the second table therebeneath. A laser positioned above the first table provides a laser beam passing through the mask to the work piece, with movement of the laser following a radially inward path as the tables rotate. The masks or templates for use in this apparatus have varying configurations. However, while the apparatus of this patent may be used with paper objects or work pieces, the nature of the apparatus does not lend itself to use with the requirements of the printing industry.
It is an object of the present invention to provide a new and improved laser apparatus and process for use in laser cutting of paper.
It is another object of the present invention to provide a new and improved laser apparatus and process for use in laser cutting of moving paper.